Not much; the rapture happens to people who haven’t yet died, but the transformation seems to be the same. (The end of 1 Cor 15 indicates both the similarities and the distinctions, for example.)
Even pre-trib rapturists agree (pretty much, I think) that the post-trib rapture of believers is in effect the same bodily transformation that will occur for those already deceased. There’s some debate among them, however, about whether the pre-trib rapture will involve a similar transformation or whether it’ll be deferred until the return of those saints with Christ at the end of the Trib. And, if the latter, what exactly happens to the bodies meanwhile.
(My favorite modern Christian apocalypse series–even though I don’t quite agree with its theology at points–The Christ Clone Trilogy, goes with the idea that only the spirits of those raptured before the Trib are taken, leaving the bodies behind for resurrection later. Which has the advantage of, ironically, not looking so much like a rapture per se–since most pre-trib rapturists believe and teach the whole body will vanish, which in turn would look massively more like the Christian rapture they were predicting and thus much less likely to be explained away by survivors. Even the pre-tribs who expect the body to be taken, too, however, don’t necessarily agree on whether the transformation happens at that point or later. Plausible arguments can be made either way. I have no opinion. Incidentally, my favorite conventional Christian apocalypse novel before the CC trilogy, was a book that’s probably impossible to find today: The Seven Last Years. It kept things moving at a brisk pace, juggled its wide cast of characters very well, and had loads of heart. Unfortunately, the author (with, sadly, a quite serious prediction!) finaled things in the early 1990s! Thus explaining its lack of popularity today, I expect. I don’t much like most conventional Christian apocalypse stories, though, including Left Behind, which I have a generally low opinion of, some nifty touches notwithstanding.)
To be fair, I don’t think ‘complacency’ is quite the right word. All the pre-trib rapturists I’ve ever personally known, whenever they get it into their heads that this time it’s really real for real (and I know some who always take that notion with a huge grain of salt, too ), desperately want to increase evangelism, because they want as many people as possible to escape the coming tribulation. But of course, they tend to disregard any future social or cultural issues beyond a particular short-term point as nothing for them to be concerned about (except as evidence that the trib, and the escape rapture, is on the way). Maybe that disregard could be considered ‘complacent’, but it isn’t as though they aren’t concerned at all about what will be happening then. Just that they won’t be around (they think) to affect events, or be affected by them, so why prepare for them?–better to focus their preparations elsewhere, from a practical perspective.
Two-and-a-half! (On standard pre-trib rapture timing of events.)
Not counting whatever happens at the end of the millennial reign of Christ, when Satan is released again to deceive the world, and there’s another rebellion, thrown down by Christ and leading into the lake of fire judgment. (Assuming that’s not only a legitimate prophecy in a legitimately canonical text, but also not just another repeat of continually repeating visions or something of that sort. For which there’s some good evidence, too. Though on the balance I tend to think that part is meant to be understood sequentially.)
But yeah, I’m positively agnostic about a lot of the timing and how it’ll be fulfilled with which people etc. I’m not sure if we’re even supposed to be clear about particulars–I rather doubt it. (Neither the angels nor even the Son, but only the Father knows, etc.)
I prefer Lewis’ attitude (following MacDonald): it’s fun and interesting to try to hash things out, but our responsibility is to be doing what Christ tells us until then.